so after the past few days with temps at MINUS 20 or lower, it would be nice to hit the defrost but get heat.
the defrost , as most of you know, uses the ac compressor to blow dry air...but its not a hot air..its mixing hot and "Air Conditioned" air. When on mixed..( defrost and floor) it still uses compressor so not as hot.. When you switch away from defrost or mixed mode...you instantly have hot air.
Cars can defrost without the use of AC...olden days...cars with no AC.

Believe me....when you have days of minus 20 or lower...it would be nice to have real heat...but at those temps...you need air blowing on windshield
Otherwise I have to drive and constantly switch between defrost and dash heater vents to get warm


sooo….tomorrow Ill go play....but

if I pull fuse #11 in engine compartment listed as Air Conditioning System, will this eliminate the compressor from kicking on .
I don't see a fuse labeled just heater motor.

If that wont cure it....eliminate compressor kicking on....any ideas ?

coutesy of @TheDurk ; "Clutch relay is behind glove box, left side about knee high. It has a dark gray 2-row 10-pin pin plug". if you disconnect the relay the compressor is not going to come on. .

I'd leave the fuse alone, there's rarely just one thing on a fuse so it'll probably knock out some of your climate control as well. Agree on pulling the relay or better yet, just unplug the wire connector on the A/C unit. Done.

Don’t recall the fuse number, believe 10 amp, labeled as AC under hood. Pulling that one stops the compressor clutch. I pulled it on my 99 when the compressor started howling.

So it depends on the year and if you have the electronic or manual climate control. But on my 2000 I disabled the auto a/c with defrost. You just have to unplug an electrical connector right behind the climate control bezel. Best part is you can still push the A/C button if you need extra help defrosting. Heres a picture

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This worked on my '97 SR5.

Works great on my ‘98....unplug that thing now!!

@3bears If the other suggestions for the hvac controls don't work then I recommend unplugging the connector on the compressor. Can't engage the clutch without that being connected. If you're really committed you could take the ac belt off.

The compressor should not run below a certain temperature on defrost.
I can't recall what it is but I'll try and test it over the next couple of days.

-20 already???????

Same. Just did this a couple weeks ago when replacing bulbs. On mine it was a connector with two blue wires at the far right side (passenger) of the hvac control.

Now I just leave the control setting on defog/footwell whereas before I was always pissed that leaving in defrost was engaging the a/c and busting my fuel economy. I've already noticed a 0.42% increase in gas mileage.

@phattyduck has a little write up on his build thread about how to do this

How is the AC compressor triggered? By the defrost button or a low temperature startup?

IMO it's a good idea to leave this alone because running the AC occasionally helps lubricate the seals and prevent failure.

This is on our 97....

We have a slider control, slide all the way to defrost and AC kicks on. Slide one spot to the left (defrost/feet) - there's an ability to be at the defrost/feet, then slide just before the AC switch is kicked on. You will still have a little air run to your feet, but majority of air runs through the windshield defroster.

I can’t really say how it get engaged but it will turn on automatically with the defrost.

You can still turn on the AC if the connector is unplugged by pushing the AC button. This mod gives more flexibility when using defrost. Also as mentioned why have the compressor on just to use more fuel if you don’t need it on?

yep...bit chilly....got to minus 26 yesterday high of -13. today only supposed to get to 5 for a high

if there is a limit switch to keep it from kicking on if too cold outside....its not working.. or maybe has to get to minus 30